Lamp



Sept. 2, 1958 E. P. NEMr-:s 2,850,661

LAMP

Filed Dec. 3, 1956 IN1/EMME.

United States Patent 2,850,6i Patented Sept. 2, 195213 free LAMP

Elmer P. l,Naines*Hollywood Calif., assigner Ato Remis Researcn lne., Los Angeles, Calif., a corporation of California Application December 3, 1956, Serial No. 525,688

3 Claims, (Cl. S13-215) This invention relates to electrically energized lamps for the production of high intensity illumination in visible spectrum.

it is an object of the invention to produce a lamp which is small in size and one which produces intense illumination without operating at excessive temperatures, thereby providing a long operative life. Another object of the invention is to provide such a lamp which may be operated from the conventional 1l() and 220 volt, 50 and of: cycle per second supplies without requiring step-up transformers or rectifiers.

lt is another object of the invention to provide a lamp in which the illumination is produced by a combination of incandescent filaments and gases or vapors excited by electric discharge. Another object of the invention is to provide such a lamp which utilizes a plurality of incandescent laments in conjunction with the electric discharge gas excitation.

t is a further object of the invention to provide a lamp which may be manufactured and operated without requiring the creation or maintenance of a high vacuum condition within the lamp. Another object of the invention is to provide such a lamp which may be produced and operated with an internal pressure in the range of zero to two-thirds of an atmosphere absolute.

lt is another object of the invention to provide a lamp which is cooled by a target adjacent the filaments thereof, the target being constructed of a metal which absorbs oxygen on heating and gives olf oxygen on cooling. A further object of the invention is to provide such a lamp which is also cooled by a heat sink comprising a metal jacket surrounding the electrical conductors therein. Another object of the invention is to provide such a lamp having a cooling iiuid conductor positioned within the lamp and surrounding the jacket.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. The drawing merely shows and the description merely describes preferred embodiments of the present invention which are given by way of illustration or example.

in the drawing:

Fig. l is a sectional view of a preferred embodiment of the invention, taken along the line 1 1 of Fig. 2;

Fig, 2 is a sectional view taken along the line 2 2 of Fig. l; and

Fig. 3 is a partial sectional View of an alternative embodiment of the invention shown in Fig. l.

There are two sources of illumination in the lamp of the invention, namely, one or more resistance type lilaments which are heated to incandescence by electric currents therein and a gas or vapor which is excited by an electric discharged therethrough. The elements of the lamp are contained within a housing or case which may be a cylindrical shell having a base 11 at one end and a transparent plate i2 at the other end. The base il' may be of glass or other suitable insulating material and has a plurality of electrical feed-through conductors 13 mounted therein and extending from both sides for making electrical connections between the elements within the lamp and the surrounding equipment. The transparent plate l2 may be made of quartz, pyrex or other high temperature resistant transparent material and is mounted in a recessed section i4 of the case 1li. The base ll the plate l2 are sealed in place in the case 10 so that the interior thereof may be evacuated. A length of tubing i5 is positioned in the wall of the case l@ providing for evacuation or injection of gas into the interior of the lamp.

A jacket i9 is positioned within the case 16, being supported by eight brackets Ztl which extend inward from the inner wall of the case lll. The jacket is open at each end thereof and extends nearly the entire length of the case from adjacent the base 11 to adjacent the plate l2, preferably being of the same configuration but smaller than the case, permitting uniform spacing from the case and creating a minimum of waste space. lt is understood that the case could take any form, the cylindrical shape producing a more uniform distribution of light and heat. The primary function of the jacket l) is to serve as a heat sink to conduct heat away from the heat producing elements of the lamp. Therefore, the jacket should be made of a good heat conducting material, preferably a metal, such as stainless steel, copper or nickel. A length of tubing is formed into a plurality of turns 21 which are positioned around the jacket 19 and the recessed section ld of the case 1li, preferably being in intimate contact therewith. Ends 22 and 23 of the length of tubing are positioned in the wall of the case lli and pass therethrough, permitting continuous ilow of Huid through the turns of tubing 21 for conducting heat from the interior of the lamp.

The jacket 19 also provides support for a target 27 and a filament structure 28, both positioned near the transparent end of the lamp. A block 29, forming a part of the filament structure 23 of Fig. l, is positioned within the jacket 19 adjacent one end thereof by four brackets 3u extending inward of the inner wall of the jacket. The block 2? is preferably a mirror having a concave upper surface Eil which directs illumination outward through the transparent plate 12 and reduces the radiation of heat towards the base 1l.

A plurality of filaments 35, 36, 37, 38, 39 are supported on hangers Litl which are mounted in and extend upward from the block 29, the filaments preferably being disposed inconcentric circles and in a single plane, thereby providing a uniform illumination intensity. Each of the larnents 3S through 39 may be similar to the filaments used in conventional incandescent lamps and is preferably made from a high temperature resistant material such as tungsten or the like. The outermost lilament 39, being the longest, is preferably proportioned so that it may be connected directly across the supply source, such as a or 220 Volt line. The remaining filaments are made from the same type and size of Wire and have the same turn diameter and spacing so that, with equal currents therein, equal intensities of illumination will be produced. Equal currents may be provided for each filament by connecting each to a supply having a different voltage or by connecting a resistor in series with each to make the resistance of all of the series comhinations equal so that all the series combinations may be connected to the same supply.

Each end of each of the filaments is connected to one of the feed-through conductors 13 by respective individual conductors 41 which pass through the block 29 and are positioned within the jacket i9. The target 27 is connected to one of the conductors il by a conductor 42.. if desired when dropping resistors are connected in series Y electric discharge.

' temperature of the filaments of the` lamp.

Vwith each of' the filaments, the resistors could be posi-V tioned within thecase of the lamp, thereby requiring only two feed-through conductors 13. However,` it is advantageous in theroperation of the lamp of the invention to provide two conductors 41 and twofeed-through conductors 13 for each filament so that greater Yheat transfer from'the filament area is achieved, thereby contributing to a lower operating temperature anda longer operating life. Y Y

After the lampfof the invention has been assembled as described above, the interior thereof is partially evacuated through the tubing 15 and then ashed with an electric discharge lamp gas. The term dashed as Vused herein means the injection of a very smallfamou'nt of gas into the-interior ofi the case, theramount of gas in'- volved being in the order ofa few molecules, not being Van'amountgreat enough Vto' make a significant change ingthelpressure within ythe case. Animportant feature of thelinvention is the fact that itis not necessary to evacuate the interior of-therlamp to anything approaching absolute! zero pressure, nor is' it necessary to provide an inerti gas within the lamp. Satisfactory operation is obtained `when' the .pressure within the lamp is not more than two-thirdsof an atmosphere absolute, the preferable operating point being in theorder of one-half atmospherel absolute. The electric discharge lamp gas which is flashed into the lamp may be hydrogen, sodium, mercury or any of the noble gases, such as helium or argon, argon andV hydrogen being preferred since they produce the maximum amount of illumination. Y Y

V.When the lamp is connected to a suitable source, an Velectric discharge is created between the target 27 and the various laments. This, discharge excites the` electric discharge lamp gas within the case and providesillumi-Y nation in addition to thatjof the incandescent filaments. The target27 Vis made of a suitable highV temperature resistant'electrical conducting material such as tungsten,

v platinum, rhodium or gold. The Vtarget is constructed to encircle the filaments and is positioned adjacent the outermost filament 39 in order to create the desired It is preferred that the target be Ymade of platinum or other material having the property of absorbingroxygen as its temperature increases and givingoif oxygen as its temperature decreases. The absorption of oxygen by the platinum when the platinum is heating up produces a cooling action in the surrounding Yatmosphere and materially reduces the operating It has been found that the mass of platinum providedl in thetarget 27am-ust be at VVleast one and one-halfV times the mass of the-filaments in order to performV an adequate cooling operation.l It has also been found that an increase of the-mass ratio to more than two to one does not produce an improvement in the cooling operation. "Therefore, itis preferred that the .target 27 be made of platinum and have aA mass in the range of one and one-half to two times that of the mass ofY the filaments.

A lamp constructed in theform of Figs. l andZ with five concentric:V filaments, the outer filament being about two and one-half inches in diameter, and the target beingY spaced about" one centimeter from the outer filament, with the over-all Vdiameter of the Ycase beingY about,V four inches,V draws approximately forty amperes from -a 220 volt'60 cycleper second source. In this unit, dropping resistors were provided.. outside the case in series with earch of the'vfilaments except' the outermost to provide equal current densities in the plainents.V

4 K ported by the jacket 19 across the end thereof.V A plurality of l'1angers..46,.similarY to.thehangers 40,,.arecused to support the filaments, each having one end thereof wrapped around the support member 45 with the other end thereof projecting upward therefrom and engaging a portion of the filaments,

A lampconstructed in accordance with the teachingsV of this invention will operate at a considerably lower i l. In a lamp, the combination of: a case; a plurality Y of incandescent lamp filaments; means for supportingV said filaments within said case; means for connecting an electrical potential to the ends of said filaments; a platinum target, the mass of said target being at least one androne-half times as great as the mass of saidvfilaments;

meansV for supporting said target within saidY case adjacent said filaments; and means for electrically connecting said target in circuit with one of said filaments.

2. In a lamp, the combination of: a case which has been evacuated to vabout one-half atmosphere and Viiashed with an electric discharge lamp gas; a Yplurality of incandescent lamp filaments; means for supporting said filaments within said case with said iilamentsequally spaced and lying in a plane; means for'connectingany electrical potential to the Vends of said'filarnents; a-platinum target surrounding said iilaments and lying insaid plane, the

. mass of said target beingat least one and one-half times therein; a plurality of incandescent lamp filaments, saidV filaments being substantiallyequally spaced over a zone in a plane; means for supporting saidlaments within said case; conductor means for electrically connecting the` ends of said laments to said feed-throughelectrical con- Y nectors; a metal jacket encircling and spaced from-said An alternative construction for supporting the vllament's A f is yshown in Fig. 3, wherein' any insulating support member 45, which may Vbef-ini thei shape of a cross, Vis sup- .conductor means, said jacket extending from adjacent saidfeed-through connectorsto adjacentrsaid filaments, .the end of said jacket adjacent said filaments terminating in a platinum target encircling said filaments with said target `lying in said plane and substantially constantly Vspaced vfrom the periphery of said zone, the mass of said target being at least one and one-half times as great as the mass of said filaments; means for supporting said jacket within said case; and means for electrically connecting said target in circuit Vwith one of said filaments.

References Cited in the tile of this patent UNITED STATES PATENTS 

